Why TFL Means You Can Skip Medigap and Part D

Last reviewed: 2026-08-11

If you have TRICARE For Life (TFL) and someone offers to sell you a Medigap policy or a Medicare drug plan, the honest answer is almost always the same: you already have this. TFL fills the gaps Medigap is built to fill, and your TRICARE pharmacy benefit already meets Medicare’s bar for drug coverage. Paying for either one usually means paying twice for something you already have for free.

Medigap duplicates what TFL already pays

TFL is Medicare-wraparound coverage. Once you have Medicare Part A and Part B, TFL automatically pays second, covering most of the deductibles, coinsurance, and copayments Medicare leaves for you to pay. That is exactly what a Medigap policy is designed to do: fill the gap between what Medicare pays and what you owe.

Since TFL already closes that gap for covered care, at no monthly premium beyond what you already pay for Part B, adding a Medigap policy on top of it typically buys you nothing new. You would be paying a Medigap premium every month for protection you already carry through TFL.

Your TRICARE pharmacy coverage already counts

Medicare Part D is prescription drug coverage you can buy from a private insurer. Whether you need it depends on whether the drug coverage you already have counts as “creditable,” meaning Medicare considers it at least as good as a standard Part D plan.

Your TRICARE pharmacy benefit, run through the TRICARE Pharmacy Program and administered by Express Scripts, is creditable coverage. That has two practical effects. First, you do not need to buy a separate Part D plan to have drug coverage, because TRICARE already provides it. Second, and just as important, you can decline Part D now without setting yourself up for a penalty later. Medicare’s late-enrollment penalty for Part D is triggered by going 63 days or more without any creditable drug coverage. As long as you keep your TRICARE pharmacy benefit, that clock never starts.

Buying a Part D plan on top of TRICARE pharmacy coverage does not protect you from anything you are not already protected from. It mainly adds a second monthly premium for a benefit you are already getting.

Where TRICARE’s own guidance leaves room for judgment

TRICARE’s own FAQ on this question does not tell every beneficiary to skip Part D outright. It says you do not need it, but it also lists a few situations where comparing plans might be worth your time: some Part D plans cover specific drugs that TRICARE’s formulary does not, cost structures can differ depending on what you take, and beneficiaries who qualify for Extra Help (Medicare’s low-income subsidy program that reduces Part D costs) may find a subsidized Part D plan changes the math.

That is a narrow slice of retirees, not a general recommendation. If none of those situations apply to you, and for most retirees none do, the default stands: your TRICARE pharmacy benefit already does the job.

The one exception worth naming

The genuine exception here is income-based, not something a sales pitch will surface for you. If you have limited income and resources and might qualify for Extra Help, a subsidized Part D plan can sometimes beat what TRICARE pharmacy coverage offers on cost for certain drugs. Figuring out whether that applies to your situation is a conversation for a benefits counselor or the Social Security Administration, not a decision to make from a mailer or a call center pitch. If nobody has raised income-based subsidies with you specifically, it is very unlikely to be the reason to add Part D.

Watch for the MAPD trap

One place this gets confusing is Medicare Advantage plans that bundle in drug coverage, often called MAPD plans. These are marketed separately from standalone Part D plans, but the same principle applies: enrolling means taking on drug coverage that competes with what TRICARE pharmacy already provides. TRICARE rules generally do not let you use TRICARE Pharmacy Home Delivery while you are also carrying other prescription drug coverage, so signing up for an MAPD plan without meaning to can leave you needing to sort out which coverage is actually paying for your prescriptions. If this happens to you, the fix is to call TRICARE and your new plan promptly, not to assume it will resolve itself.

What this means for your wallet

Skipping both Medigap and Part D, when neither adds real value, is not a shortcut. It is the accurate read of what you already have. TFL and your TRICARE pharmacy benefit were built to work together as a package, and for most retirees in this position, that package is already complete. The honest recommendation is to keep your money in your pocket unless one of the narrow exceptions above genuinely applies to you, and to check with a counselor before you decide it does.

Not sure what applies to you? Take the two-minute Decision Guide.